A brief tangent: I'm at the TED conference this week, and today I put on my editor hat and moderated a panel on how to change our global energy priorities, by moving away from oil/gas towards renewables. On the panel were two luminaries - Richard Sears, a VP at Shell and visiting scientist at MIT, and Dan Reicher, head of energy initiatives at Google.org (Dan was a member of the Obama transition team and on the shortlist, reportedly, to be Obama's secretary of energy). The lunch went well - among others, Bill Gates was in the audience - and it seemed a lively discussion about what can actually be done, right now, to incentivize both the oil industry as well as consumers to start the shift to other energies.

The consumer angle is especially intriguing, given the focus of The Decision Tree, since one of the items most often mentioned as a driver towards better consumer behavior - in terms of moving towards conservation and making smarter more efficient energy choices - is metrics. Reicher mentioned that the Obama stimulus package, as originally written, has something like $4 billion earmarked to go towards buying (or help buying) some 40 million smart meters for households. That's enough to change one in three households towards smarter energy usage. Smart meters are basically feedback devices that let consumers know how much energy they're using and at what times, allowing them to adjust their consumption habits to consume less (and spend less).

This is, readers will recognize, the same sort of thing that's emerging as significant for changing our health behaviors - giving people a way to see and measure, quantitatively, what they're doing - and then to calibrate adjustments. Even better: Provide for openness, and let people compare and collaborate on improving their behaviors.

A couple cool examples in the energy world are Fuelly, a website with a social networking component that let's you track how much you drive your car, what sort of mileage you're getting, and so on. This is the province of so-called hypermilers, but also folks who just want to drive less and spend less on gas - which was pretty much all of us over the summer. Another cool tool here is WattzOn (pronounced "watson"), a site developed by Saul Griffith that lets you track your overall energy consumption, from airplane travel to food production to consumer goods like clothing. OK, this borders on obsessive, and isn't entirely practical - but it does give a remarkable picture of our overall energy footprint - not just our carbon footprint - and might provide ways we could cut back (Griffith, for instance, rations the amount of airplane trips he'll go on each year).

So the parallels here are quite neat - in both circumstances (health and energy), new tools are emerging that suddenly turn our invisible lives into stark, bold numbers, numbers that we can give us insight into exactly where we stand, as well as direction for where we might want to go. In both cases, it's not going to be easy to actually stick to our principles and change how we do things. It's no easier to stop driving than it is to stop eating (or in the case of In 'n' Out burger, doing both at once). But gaining perspective on the relationship between our actions and our greater context - be it our health or our planet's health - is a necessary first step.